Method of manufacturing loaded conductors



26, 1930- w. M. BISHOP 1,773,938

METHOD OF MANUFACTURING LOADED CONDUCTORS Filed June 2 I I n I 8 I I If /Nl EN7'OP [M M BISHOP rial directly 7 served that with copper conductors, for G):

amount of stretching does not ample, a small Patented Aug. 26, 1930 UNITED STA WALTERM. BISHOP, 01 NEW YORK, NQY.

TORIES, INCORPORATED, OF

METHOD or ANUFACTURIN noannn ooivnco'rons Application filed June 6,

This invention relates to continuous loading of electrical conductors with magnetic loading material. v T

It has been proposed heretofore to apply magnetic loading materialto conductors by electrolytic deposition of'the magnetic mateuponthe conductor or spraying it thereupon in molten form to form a thin sheet or a plurality of sheets separated by an insulating layer. vIVhen-themagnetic material is thus deposited upon the conductor it is continuous from end to end and owing to the tendency of high frequencies to flow in the outer layers of the conductor the effective high frequency resistance is increased.

A problem connected with the electrolytic or spray method of deposition of magnetic materials on conductors has been to provide efficient and practlcable means of preventing this increase in effective resistance, which 1s more importantat telephone and carrierfrequencies than at telegraph frequencies. It is at these higher frequencies that the electrolytic and spray methods offer their greatest advantages from'the standpoint of provi ding a sufficiently thin layer or layers of magnetic material. in accordance with thepresent invention by stretching the conductor, after applicationof the magnetic material thereto, a suflicient amount to break up the layer of magnetic material longitudinally, it having been obcause the copper to break but does cause the magnetic loading material of the usual compositions to break transversely atfrequent intervals. The stretching may be accomplished by direct longitudinal tension, pulling the material over a Wheel of small diameter, by pulling theloaded conductor through a die, or by a combination of these or equivalent methods.

A further advantage of this stretching is that the diameter of the copper conductor is reduced to a greater extent than the diameter of the loading material which gives the loading material a certain degree of looseness desirable for developing and maintaining This problem is solved 1929. Serial No. 368,843.

satisfactory magnetic properties during the subsequent heat treatment.

A further advantage is that the longitudinal component offlux, which is present with spirally, applied loading, is absent. Y The invention is not limited to use with copper conductors but may be employedwith' conductors of a metal such as copper alloys,

copper-aluminum alloys or other suitable highly conductive' conductors which will stretch sufficiently without breaking. The method is not limited to conductorsbearing a single layer of loadingbut may be employed with those having a plurality of layers;

In practice it has been found possible to break up the magnetic material into relative- 1y short uniform lengths of the order of a centimeter or less, although less frequent breaks may be found satisfactory. The distance between breaks andhence the length of the separate pieces of loading may be very irregular under some circumstances. This, however, is entirely immaterial in most cases provided the largest distance between breaks is no longer than a few decimeters orpossibly a meter or two. The method is applicable not only to a single layer of electrolytically deposited or sprayed material but to a plurality of layers.

' A conductor manufactured in accordance with the invention is shown in Fig. 1; and a mechanism suitable for stretching the conducto-r is shown in Fig. 2. v I

In Fig. 1 the conductor 1 comprises a central copper portion. 2, and the loading 3 is indicated with cracks or breaks 4.

In Fig. 2 a supply of the loaded conductor i ill What is claimed is:

1. A method Which comprises applying magnetic loading material to an electric conductor in a continuous sheath, for example, by electrolytic methods or spraying, characterized in that the conductor is thereafter deformed sufficiently and in a manner to cause frequent transverse breaks in the magnetic material.

2. A method in accordance with claim 1 in which the deformation is accomplished by stretching the conductor.

In Witness whereof, I hereunto subscribe my name, this 3rd day of June, 1929.

VALTER M. BISHOP. 

